The windows would have to be diagnosed as to where its not getting power ie. relay,switches,connections, or if it is getting power to the motor and still not working the motor is bad. As for the locking feature I couldn't find a 2003 manual but I found a 2004 manual the procedure should be similar it starts on page 19. Here is where you can download the manual free:
http://www.autousermanual.com/view/dodge/caravan/2004/
I hope this helps you.